Command processing method and radio communication apparatus

ABSTRACT

A command processing method for a radio LAN system composed of a plurality of terminals and at least one base apparatus is disclosed which prevents users of the terminals from suffering from confusion or conflict between them with regard to handling of a command issued from any of the terminals and from misunderstanding that the system has failed. When a channel changing command or a like command is issued from a terminal, the base apparatus determines whether or not the received command is a competitive command whose acceptance may result in the disturbance of reception of data of any other terminal. If the received command is a competitive command, then the base apparatus rejects the command and issues a notification of the rejection to the terminal which has issued the command. When a particular condition is satisfied such as when the priority of the terminal which has issued the command is higher than that of any other terminal receiving data, then the base apparatus may accept the command.

BACKGROUND OF THE INVENTION

This invention relates generally to a command processing method for aradio LAN (Local Area Network) system, and a radio communicationapparatus which composes a radio LAN system.

In order to view an audio/video program, access the Internet, or performvarious other desired functions with a computer it is conventionallynecessary to maintain at least one hard-wired connection so that desireddata may be transferred from any number of remote sites to the computerfor processing, and then to an associated display device for display. Itwould therefore be beneficial to provide an improved device allowing foraccess to the above functions without maintaining such a hard-wiredconnection.

SUMMARY OF THE INVENTION

Therefore, generally speaking, in accordance with the invention, animproved display terminal for a radio LAN system is provided.

In accordance with the invention, it has been proposed to construct aradio LAN system from a plurality of apparatus and transmit and receivedata between the apparatus in a limited area such as within a house orwithin a room. To this end, the IEEE (Institute of Electrical andElectronics Engineers) 802.11 standards prescribe a 2.4 GHz and 5 GHzradio frequency bands that can be used for such a radio LAN system.

A radio LAN system of the type described includes, for example, a baseapparatus and one or more terminals. The base apparatus includes abuilt-in tuner or a tuner connected thereto for receiving a broadcastand to which a telephone circuit or the like is connected. A terminalthat communicates with the base apparatus by radio communication to senda command or other information to the base apparatus and receiveinformation such as image data and audio data from the base apparatus toallow for the display of an image on a display section and the outputsound from a speaker or an earphone is also provided. Thus, a user ofsuch a radio LAN system can enjoy a ground wave TV (television)broadcast or a BS/CS (broadcasting satellite/communications satellite)digital broadcast, access the Internet, or enjoy telephone conversationusing the display terminal regardless of the location of the user in ahouse or in a room.

In particular, a radio LAN system can be configured as is shown in FIG.1. The radio LAN system shown in FIG. 1 includes two terminals 30A and30B each including an antenna 31, a liquid crystal display (LCD)apparatus 32, a speaker 33 and a microphone 34. A base apparatus 10 isalso shown, and includes an antenna 11 for radio communication withterminals 30A and 30B and a built-in TV tuner 13 connected to an antenna12 for reception of a TV broadcast. A telephone circuit 1 is alsoconnected to base unit 10. In accordance with the radio LAN system ofthe invention, a user can use terminal 30A in a first location whileanother user can use terminal 30B in a second location to enjoy a TVbroadcast, access the Internet or enjoy telephone conversation.

In the radio LAN system in accordance with the invention including twoterminals 30A and 30B, for example, when a TV broadcast is to be enjoyedby a user, if only one of the terminals is in use and receives thebroadcast, then the user can freely change the channel. However, whenboth of terminals 30A and 30B are in use and receive the broadcastsimultaneously, a problem arises with regard to channel selection.

If the system is configured such that the channel to be received by theTV tuner 13 in base apparatus 10 is changed by base apparatus 10 eachtime a channel changing command is issued from one of the terminals,then each time a channel changing command is issued from any of theterminals, the broadcast channel to be received by the terminals 30A and30B is changed for both terminals. As a result, confusion or conflict inchannel selection occurs between the user of terminal 30A and the userof terminal 30B.

While terminals 30A and 30B receive the same broadcast channel Xsimultaneously, if a command for changing the channel to a channel Y isissued from terminal 30A and another command for changing the channel toa channel Z is issued immediately or substantially simultaneously fromterminal 30B, then the channel is changed to channel Z (the secondrequested channel) on both of terminals 30A and 30B. Consequently, theuser of the terminal 30A who has requested the channel selection tochannel Y may assume that the system has failed.

In accordance with the invention, an improved command processing methodand radio communication apparatus for a radio LAN system is providedcomposed of a plurality of terminals and at least one base apparatuswhich prevents users of the terminals from suffering confusion orconflict between them when issuing command from the terminals.

According to an aspect of the present invention, there is provided amethod for processing commands for a radio LAN system that includes aplurality of terminals and at least one base apparatus. In the system,commands issued from any of the terminals are received by the baseapparatus. Information is transmitted from the base apparatus to theterminals by radio communication. The base apparatus first receives acommand issued from any of the terminals. The base apparatus thendetermines whether or not the received command is a competitive commandwhose acceptance may result in the disturbance of any other terminalthat is receiving information. If it is determined that the receivedcommand is a competitive command, the command is rejected. Anotification of the rejection to the terminal which has transmitted thecommand is issued.

The command processing method includes an alternative embodimentincluding the feature that a priority order among the terminals may beset. Thus, even if a received command is a competitive command, if thepriority of the terminal which has transmitted the command is higherthan that of any of the other terminals that is currently receivinginformation, then the base apparatus accepts the command and issues anotification of the acceptance of the command to the other terminal orterminals.

In another alternative embodiment, a command processing method may beconstructed such that, even if a competitive command is received, if apredetermined time or more has elapsed after implementation of aprevious command regarding a process being currently executed by anyother terminal, then the base apparatus accepts the command and issues anotification of the acceptance of the command to the other terminalsthat are a receiving state.

In accordance with another alternative embodiment of the invention, acommand processing method may be constructed such that, if a competitivecommand is received, then the base apparatus issues to the otherterminals that are receiving information an inquiry whether the commandmay be accepted. If a reply from the other terminals accepts thecommand, the command is then accepted by the base unit.

According to another aspect of the invention, a radio communicationapparatus for a radio LAN system is provided that includes a pluralityof terminals and at least one base apparatus. A command issued from anyof the terminals is received by the base apparatus and information istransmitted from the base apparatus to the terminals by radiocommunication. The radio communication apparatus is located in the baseapparatus. The radio communication apparatus comprises a receiver forreceiving a command issued from any of the terminals, and adiscriminator for determining, when a command issued from any of theterminals is received by the reception means, whether the command is acompetitive command whose acceptance may result in disturbance of thereception of information by any other of the terminals. Based upon aresult of the determination, it is determined whether or not the commandshould be accepted. Finally, when it is determined that acceptance ofthe command should be rejected, a notification of the rejection of thecommand is transmitted to the terminal which transmitted the command.

In the command processing method and the radio communication apparatusin accordance with the invention, if a competitive command is issuedfrom a terminal, it is generally not accepted by the base apparatus.Therefore no disturbance or conflict occurs among the users of theterminals in regard to handling of a command issued from one of theterminals. If the command is not accepted, then a notification of such arejection is issued from the base apparatus to the terminal whichoriginally transmitted the command. Therefore, if the command is notaccepted, the user of the terminal which has issued the command does notthink that the system has failed.

Still other objects and advantages of the invention will in part beobvious and will in part be apparent from the specification and thedrawings.

The invention accordingly comprises the several steps and the relationof one or more of such steps with respect to each of the others, and theapparatus embodying features of construction, combination(s) of elementsand arrangement of parts that are adapted to effect such steps, all asexemplified in the following detailed disclosure, and the scope of theinvention will be indicated in the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic view showing an example of radio LAN system;

FIG. 2 is a schematic view showing an example of a radio LAN system towhich a command processing method according to an embodiment of theinvention is applied;

FIG. 3 is a block diagram showing an example of functional blockconfiguration of a base apparatus of the radio LAN system of FIG. 2;

FIG. 4 is a block diagram showing an example of functional blockconfiguration of terminals of the radio LAN system of FIG. 2; and

FIGS. 5 to 7 are flow charts illustrating different forms of a commandprocessing method according to an embodiment of the invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

FIG. 2 shows an example of radio LAN system to which a commandprocessing method according to the present invention can be applied.Referring to FIG. 2, the radio LAN system shown includes a baseapparatus 10 and two display terminals 30A and 30B.

A telephone circuit 1 is connected to base apparatus 10. Base apparatus10 includes an antenna 11 for radio communication with display terminals30A and 30B so that display terminals 30A and 30B are able to performtelephone communication as desired utilizing radio communication withbase apparatus 10 (as will be described below) and access the Internet.Of course, any manner for accessing the Internet may be employed bydisplay terminals 30A and 30B, as long as this method of access isproperly connected to base unit 10.

Further, an antenna 12 for receiving a ground wave television broadcastand another antenna 14 for receiving a BS/CS digital broadcast areconnected to the base apparatus 10. A tuner 13 and a BS/CS tuner 15 arebuilt into base apparatus 10 so that display terminals 30A and 30B canreceive video and audio information of a ground wave televisionbroadcast and a BS/CS digital through radio communication with baseapparatus 10. Of course, rather than an antenna, a cable feed wire orother transmission media for a television broadcast may be coupled withbase apparatus 10. In accordance with such a configuration, tuners 13and 15 would be configured to allow a user to select from among variousaudio/video programs provided via the provided transmission media.

Furthermore, a playback apparatus such as a DVD player may be connectedas an external apparatus 50 so that the display terminals 30A and 30Bcan receive audio/video program information and so forth played back byexternal apparatus 50 through radio communication with base apparatus10. While a DVD player is shown, any appropriate playback device may beemployed.

A remote controller transmitter 29 such as a remote controller mouse orthe like is connected to base apparatus 10. An infrared remote controlsignal transmitted from remote controller transmitter 29 is received bya remote control signal reception section 51 provided on externalapparatus 50 to control external apparatus 50. Of course other controldevices, such as a radio wave remote control, or hardwired controllermay be provided for allowing control of external apparatus 50.

Display terminals 30A and 30B (collectively “display terminal 30”) willnow be described. Display terminal 30 includes an antenna 31 for radiocommunication with base apparatus 10, a liquid crystal display (LCD)apparatus 32 for displaying an image, a speaker 33 for outputting sound,and a microphone 34 for inputting sound. Display terminal 30 furtherincludes a key selection and operation section 35 including a powersupply key, an Internet key, an electronic mail key, a channel selectionkey, a sound volume adjustment key and the like.

Further, a touch panel 36 is provided on a screen of LCD apparatus 32 sothat, when a user touches touch panel 36 within a predetermined region,a control panel 37 is displayed on LCD apparatus 32. A user can touch akey switch section of control panel 37 to control various functions ofbase apparatus 10, such as requesting a channel change.

Base apparatus 10 is functionally configured as shown in FIG. 3 whiledisplay terminal 30 is functionally configured as shown in FIG. 4, aswill now be described.

Referring next to FIG. 3, base apparatus 10 includes a key operationsection 16 and a display section 17 which function as a user interfacebetween the user and base apparatus 10. Key operation section 16 isconnected to a main control section 21 through an interface section 18.Display section 17 is connected to main control section 21 through adisplay control section 19. Remote controller transmitter 29 isconnected to main control section 21 through an interface section 28.

A signal of a ground wave television broadcast selected and demodulated,and then converted into digital image data by tuner 13 from a datasignal received by antenna 12, and is then sent to acompression-decompression section 24. A signal of a BS/CS digitalbroadcast is selected and separated into compressed image data andcompressed audio data. The separated data are then decompressed by BS/CStuner 15, and are sent to compression-decompression section 24.Telephone circuit 1 is connected to compression-decompression section 24through a circuit interface section 25 and is also connected to a signalcontrol section 23 through a modem section 26.

Furthermore, external apparatus 50 reproduces and outputs data tocompression-decompression section 24, via external input interface 52.

Compression-decompression section 24 compresses video data and audiodata from TV tuner 13, BS/CS tuner 15, external input interface 52 andcircuit interface section 25 in accordance with a predeterminedcompression system such as, for example, the MPEG (Moving PictureExperts Group) system. The compressed video data and audio data areforwarded to signal control section 23.

Further, compression-decompression section 24 decompresses compressedaudio data transmitted thereto from display terminal 30. This compressedaudio data is received by a radio communication section 22 and thenforwarded from radio communication section 22 tocompression-decompression section 24 through signal control section 23.The decompressed audio signal data is then forwarded to circuitinterface section 25.

Radio communication section 22 modulates data forwarded from signalcontrol section 23 in accordance with a predetermined modulation systemsuch as, for example, the CCK (Complementary Code Keying) system or theOFDM (Orthogonal Frequency Division Multiplexing) system, for example.The modulated data is then converted into a high frequency signal in the2.4 GHz band or the 5 GHz band. The high frequency signal is thentransmitted from antenna 11 to display terminal 30. Radio communicationsection 22 also converts a high frequency signal transmitted theretofrom display terminal 30 and received by antenna 11 into an intermediatefrequency signal, demodulates the intermediate frequency signal andforwards the demodulated data to signal control section 23.

Signal control section 23 arbitrates and selectively forwards video dataand audio data compressed by compression-decompression section 24, datareceived by modem section 26 and control data from main control section21 to radio communication section 22. Further, signal control section 23selectively forwards data transmitted from display terminal 30 andreceived by radio communication section 22. This received data is thenforwarded from radio communication section 22 to signal control section23, and from signal control section 23 to main control section 21, modemsection 26 and compression-decompression section 24.

Main control section 21 controls the components of base apparatus 10.Main control section 21 comprises, though not shown in FIG. 3, a CPU(Central Processing Unit), a ROM (Read Only Memory) in which programs tobe executed by the CPU, fixed data and so forth are written, a RAM(Random Access Memory) which functions as a working area of the CPU andother necessary elements.

Referring next to FIG. 4, display terminal 30 constructed in accordancewith the invention includes a main control section 41 to which keyoperation section 35 is connected through an interface section 38.Further, a coordinate detection section 39 is provided as an interfacefor touch panel 36 and detects coordinates of a touched position oftouch panel 36. The detected coordinate values are forwarded to maincontrol section 41.

If touch panel 36 is touched in the predetermined region thereof, thenmain control section 41 controls a display control section 45 to displaycontrol panel 37 on LCD apparatus 32. Then, if the key switch section ofcontrol panel 37 displayed on the LCD apparatus 32 is touched, maincontrol section 41 produces control data in response to the touchedposition of the key switch section. Further, if key operation section 35is operated, main control section 41 produces control data in responseto the operated key. The control data produced by main control section41 is forwarded to a signal control section 43.

In display terminal 30, an audio signal from microphone 34 is amplifiedby an audio amplifier 48 and converted into digital audio data by an A/D(analog to digital) converter 49. The audio data is compressed inaccordance with a predetermined compression system by acompression-decompression section 44. The compressed audio data is thenforwarded to signal control section 43.

Signal control section 43 arbitrates and selectively forwards controldata from main control section 41 and audio data compressed bycompression-decompression section 44 to a radio communication section42. Further, signal control section 43 selectively forwards datatransmitted from base apparatus 10 and received by radio communicationsection 42. Control and other data that are previously received by modemsection 26 of base apparatus 10 are forwarded to main control section41, while compressed video data and audio data are forwarded tocompression-decompression section 44.

Radio communication section 42 modulates data forwarded from signalcontrol section 43 in accordance with a predetermined modulation system,converts the modulated data into a high frequency signal in the 2.4 GHzband or the 5 GHz band and transmits the high frequency signal fromantenna 31 to base apparatus 10. Further, radio communication section 42converts a high frequency signal transmitted from base apparatus 10 andreceived by antenna 31 into an intermediate frequency signal,demodulates the intermediate frequency signal and forwards thedemodulated data to signal control section 43.

Compression-decompression section 44 decompresses compressed video dataand audio data forwarded from signal control section 43. Thedecompressed video data is displayed as an image on LCD apparatus 32under the control of display control section 45. The decompressed audiodata is converted into an analog audio signal by a D/A (digital toanalog) converter 46, is amplified by an audio amplifier 47 and isoutput as sound from speaker 33.

Main control section 41 controls the components of display terminal 30and includes, though not shown in FIG. 4, a CPU, a ROM, a RAM and soforth similarly to main control section 21 of base apparatus 10.

In order to receive a ground wave television broadcast or a BS/CSdigital broadcast at display terminal 30 in the radio LAN systemdescribed above, video data and audio data from TV tuner 13 or BS/CStuner 15 of base unit 10 from a selected channel are first compressed bycompression-decompression section 24. This compressed data is thentransmitted by radio communication section 22 under the control ofsignal control section 23 to display terminal 30. In display terminal30, the compressed video data and audio data are first received by radiocommunication section 42. This received data is then forwarded to anddecompressed by compression-decompression section 44 under the controlof signal control section 43. Consequently, an image is displayed on LCDapparatus 32 and sound is output from speaker 33.

If a user selects a channel of a TV or BS/CS broadcast using keyoperation section 35 or control panel 37, a command indicating thedesired channel is transmitted from main control section 41 of displayterminal 30 to the base apparatus 10 by radio communication section 42under the control of signal control section 43.

In base apparatus 10, the transmitted command is received by radiocommunication section 22 and sent to main control section 21 under thecontrol of signal control section 23. Main control section 21 controlstuner 13 to select a channel in accordance with the received command.

In order to view and hear data played back by external apparatus 50, theuser initiates a playback operation through key operation section 35 orcontrol panel 37. In response, a command is transmitted from terminal 30to base apparatus 10 requesting playback of data by external apparatus50.

External apparatus 50 is controlled in accordance with a commandtransmitted by remote controller 29. Desired image and audio data aretherefore played back by external apparatus 50. Image and audio dataoutput from external apparatus 50 are transmitted from base apparatus 10to terminal 30 in a manner similar to that noted above. At terminal 30an image is displayed on LCD 32 and sound is output from speaker 33 inaccordance with the received image data and audio data, respectively.

In order to access the Internet, a user operates key operation section35 or control panel 37 to request connection to an ISP (Internet ServiceProvider). The request is transmitted from main control section 41 ofdisplay terminal 30 to base apparatus 10 by radio communication section42 under the control of signal control section 43.

In base apparatus 10, a request is received by radio communicationsection 22 and is forwarded to main control section 21 under the controlof signal control section 23. Consequently, modem section 26 and circuitinterface section 25 are controlled in response to the request by maincontrol section 21 to establish a connection to the ISP. Then, forexample, data sent from the ISP to telephone circuit 1 in response tothe access request to a certain homepage is sent to signal controlsection 23 through circuit interface section 25 and the modem section26. This data is in turn transmitted to display terminal 30 by radiocommunication section 22.

In display terminal 30, the data is received by the radio communicationsection 42 and sent to main control section 41 under the control ofsignal control section 43. Main control section 41 processes the data toproduce display data. This display data is then forwarded to displaycontrol section 45 so that the retrieved homepage is displayed on theLCD apparatus 32. Of course, access to the Internet may be performedemploying any other type of provided ISP connection, including but notlimited to cable transmissions, satellite transmissions, DSLtransmissions, or any other information data transmission medium.

In order to perform the function of allowing for a telephoneconversation, a transmission audio signal from microphone 34 of displayterminal 30 is converted into digital audio data by A/D converter 49 andcompressed by compression-decompression section 44. Then, the compressedaudio data is transmitted to base apparatus 10 by radio communicationsection 42 under the control of the signal control section 43.

In base apparatus 10, the compressed audio data is received by radiocommunication section 22. This received data is in turn forwarded to anddecompressed by compression-decompression section 24 under the controlof signal control section 23. Then, the decompressed transmission audiosignal is forwarded to telephone circuit 1 through circuit interfacesection 25.

Meanwhile, a received audio signal transmitted over telephone circuit 1is sent through circuit interface section 25 tocompression-decompression section 24 where it is compressed. Thecompressed audio data is transmitted to display terminal 30 by radiocommunication section 22 under the control of signal control section 23.

In display terminal 30, the compressed audio data is received by radiocommunication section 42. This received audio data is forwarded to anddecompressed by compression-decompression section 44 under the controlof signal control section 43. Then, the decompressed audio data isconverted into an analog audio signal by D/A converter 46 and output asa voice from speaker 33.

Different forms of command processing methods according to the inventionwill now be described. A command issued from the terminal 30A or 30B isprocessed by the base apparatus 10 in the radio LAN system describedhereinabove.

According to the command processing method of the present invention, ifa command issued from terminal 30A or 30B is a competitive command, thenthe base apparatus 10 does not accept the command. A competitive commandis one that would disturb the reception of information by anotherterminal from the base apparatus. For example, if a channel selectioncommand is issued from terminal 30A while the power supply to terminal30B is off and terminal 30B is not in receiving information, then thecommand is not a competitive command. On the other hand, if a channelchanging command is issued from terminal 30A while terminals 30A and 30Bare receiving the same channel from the base apparatus, then the commandis a competitive command.

In the command processing method of the invention, when a command is acompetitive command and therefore is not accepted, base apparatus 10issues a notification to the terminal from which the command has beentransmitted indicating that the command could not be accepted. In theterminal receiving the notification, a message such as “This commandcannot be accepted.” is displayed on LCD 32 or is output from speaker 33under the control of main control section 41.

Identification information (ID) for identification of the terminal whichtransmits a command is added to the command transmitted from terminal30A or 30B to base apparatus 10. Also, ID for identification of theterminal of the destination of a response to command is added to anotification transmitted from base apparatus 10 to terminal 30A or 30B.

Several detailed examples of the command processing method according tothe present invention will now be described.

Referring next to FIG. 5, a priority order is determined betweenterminals 30A and 30B. In other words, priority is given to one ofterminals 30A and 30B.

However, the priority need not necessarily be given permanently to oneof the terminals. For example, priority may be given to terminal 30A or30B depending upon a current time. Thus, priority may be given toterminal 30A from 6:00 a.m. to 6:00 p.m. but to terminal 30B from 6:00p.m. to 6:00 a.m. Priority may also be determined based upon the day ofthe week such that priority is given to terminal 30A from Monday toFriday but to terminal 30B on Saturday and Sunday. The desired priorityorder is set by the user in main control section 21 of base apparatus 10through key operation section 16 of base apparatus 10.

In the first example in accordance with the invention, main controlsection 21 of base apparatus 10 executes a command processing routine 60as illustrated in FIG. 5. In accordance with command processing routine60, even if a received command is a competitive command, if the terminalwhich has issued the command has priority, then the command is acceptedand a notification of the acceptance of the command is sent to the otherreceiving terminals.

In particular, referring to FIG. 5, a command is received by baseapparatus 10 from one of the terminals. At step 61 it is determinedwhether the command is a competitive command. If it is determined thatthe command is not a competitive command, then processing advances fromstep 61 to step 62, in which main control section 21 of base apparatus10 accepts the command. Accordingly, if no other terminal is receivinginformation, then the user of the terminal can change the channel freelyirrespective of whether or not the user has the priority.

However, if it is determined in step 61 that the received command is acompetitive command, then the processing advances from step 61 to step63. At step 63 main control section 21 determines whether the terminalthat has issued the command has priority. If it is determined that theterminal issuing the command does not have the priority, then processingadvances from step 63 to step 64. At step 64 main control section 21 ofbase apparatus 10 rejects the command and issues a notification of therejection of the command request to the terminal that issued thecommand. Accordingly, if a channel changing command is issued fromterminal 30A while terminals 30A and 30B are simultaneously receivingthe same channel, if terminal 30A does not have priority, then thechannel changing command from terminal 30A is not accepted.

If it is determined in step 63 that the terminal that issued the commandhas priority, then processing advances from step 63 to step 65. At step65 main control section 21 of base apparatus 10 accepts the command andnotifies the other terminal of this acceptance. Thereafter, processingadvances to step S66, in which base apparatus 10 performs the processrequested in the command. Accordingly, if a channel changing command isissued from the terminal 30A while the terminals 30A and 30B aresimultaneously receiving the same channel, then if terminal 30A haspriority, the channel changing command from the terminal 30A isaccepted. Because terminal 30B is notified in advance that the channelwill be changed, the user of terminal 30B is aware of the change.

Where the priority is given to terminal 30A or 30B depending upon timeor day of the week as described above, it is therefore determined instep 63 whether or not the terminal which has issued the command haspriority at the present time or day of the week. Where the priority isgiven to the terminal 30A or 30B depending upon time or day of the weekas described above, control by terminal 30A and terminal 30B can beadjusted appropriately.

Referring next to FIG. 6, main control section 21 of base apparatus 10executes such a command processing routine 70. In accordance withprocessing routine 70 if a received command is a competitive command,and the desired command is issued after a predetermined time or moreafter a beginning of a process being currently executed by the otherterminal, then the command is accepted and the other terminal isnotified. Preferably, the predetermined time represents around one totwo hours.

In particular, when base apparatus 10 receives a command from one of theterminals, at step 71, main control section 21 first determines whetherthe command is a competitive command. If it is determined that thecommand is not a competitive command, then processing advances from step71 to step 72. At step 72, main control section 21 of base apparatus 10accepts the command. Then, processing further advances to step 73, inwhich main control section 21 resets a timer to update time measurement.Accordingly, when only one terminal is in a receiving state, the user ofthe terminal can change the channel freely. Each time the channel ischanged, the timer is reset.

If it is determined at in step 71 that the command is a competitivecommand, then processing advances from step 71 to step 74. At step 74main control section 21 of base apparatus 10 determines from the timerwhether or not a predetermined time or more has elapsed after theacceptance of a prior command initiating the process being currentlyexecuted by the other terminal. If the predetermined time or more hasnot elapsed, then processing advances from step 74 to step 75. At step75 main control section 21 of base apparatus 10 rejects the requestedcommand and notifies the terminal which has issued the command of therejection. Accordingly, when a terminal is receiving a certain channel,if the user of another terminal tries to select a channel different fromthe channel being received by the first terminal, if at least apredetermined time period has not elapsed after the acceptance of apreceding command that selected the certain channel the channelselection command from the other terminal is not accepted.

If base apparatus 10 determines in step 74 that at least a predeterminedtime has elapsed, then processing advances from step 74 to step 76. Atstep 76 main control section 21 of base apparatus 10 notifies the otherterminal currently receiving data that the newly requested command willbe accepted. Then, processing advances to step 77, in which main controlsection 21 of base apparatus 10 performs a process requested by thecommand. Further, in a step 78, main control section 21 resets the timerto update the time measurement. Accordingly, in the case describedabove, if a fixed predetermined time or more has elapsed after theacceptance of a preceding command initiating a present activity from oneterminal, then channel selection command received from another terminalis accepted. The user of the one terminal is therefore notified inadvance that the channel will be changed.

Referring next to FIG. 7, main control section 21 of base apparatus 10executes a command processing routine 80. In accordance with thisembodiment of the invention, even if a competitive command is received,if the user of the other terminal which is receiving data consents toacceptance of the command, then the command is accepted.

In command processing routine 80, base apparatus 10 first determines instep 81 whether or not a received command is a competitive command. Ifthe command is not a competitive command, then processing advances fromstep 81 to step 82. At step 82, main control section 21 of baseapparatus 10 accepts the command.

If it is determined in step 81 that the command is a competitivecommand, then processing advances from step 81 to step 83. At step 83main control section 21 of base apparatus 10 issues to the otherterminal currently receiving data an inquiry whether or not the commandmay be accepted. The inquiry is performed by transmitting control datafrom base apparatus 10 to the other terminal and displaying a messagesuch as “May the channel be changed?” on the LCD 32, or outputting fromspeaker 33 on the other terminal an audio version of the question.

In response to the inquiry, the user of the other terminal operates keyoperation section 35 or control panel 37 to issue a reply representingwhether or not the command may be accepted. Reply data is transmittedfrom the other terminal to the base apparatus 10.

After the inquiry in step 83, processing advances to step 84. At step 84main control section 21 of the base apparatus 10 determines whether ornot the received reply accepts the command. If the reply objects to theacceptance of the command, then processing advances from step 84 to step85. At step 85 main control section 21 of base apparatus 10 rejects thecommand and notifies the terminal that issued the command of therejection.

If the reply consents to the acceptance of the command, then processingadvances from step 84 to step 86. At step 86 main control section 21 ofthe base apparatus 10 accepts the command and implements the requestedaction.

While the radio LAN system described hereinabove includes the singlebase apparatus 10 and the two terminals 30A and 30B, the presentinvention can be applied also to a radio LAN system which includes asingle base apparatus and three or more terminals.

In this instance, where a priority order is set among the terminals asin the first example described hereinabove, it is possible to givepriority permanently to one or more of the terminals, to permanentlygive different order numbers to the terminals, to give priority to oneor more of the terminals depending upon the time or day of the week, orto give different priority order numbers to the terminals.

In this case with three or more terminals, base apparatus 10 determines,at step 63 of command processing routine 60 of FIG. 5, whether or notthe priority of the terminal which has issued a command is higher thanthe priority of the other terminal or terminals that are currentlyreceiving data. If the priority is not higher or is equal, then thecommand is not accepted. If the priority is higher, then the command isaccepted.

Further, where the command is accepted when the user of the otherterminal consents to acceptance of the command, if a plurality of otherterminals are also receiving data, then the base apparatus 10 acceptsthe command, in step 84 of the command processing routine 80 of FIG. 7,only when the command is accepted by a majority of the plurality ofterminals currently receiving data including the terminal which hasissued the command. If the command is accepted, base apparatus 10 issuesto those terminals that objected to the command a notification that thecommand will be accepted.

Further, the present invention can be applied also to a radio LAN systemwhich is composed of a plurality of base apparatus and a plurality ofterminals.

It will thus be seen that the objects set forth above, among those madeapparent from the preceding description, are efficiently attained and,because certain changes may be made in carrying out the above method andin the construction(s) set forth without departing from the spirit andscope of the invention, it is intended that all matter contained in theabove description and shown in the accompanying drawings shall beinterpreted as illustrative and not in a limiting sense.

It is also to be understood that the following claims are intended tocover all of the generic and specific features of the invention hereindescribed and all statements of the scope of the invention which, as amatter of language, might be said to fall therebetween.

1. A command processing method for a radio LAN (Local Area Network)system which includes a plurality of terminals and at least one baseapparatus and wherein a command issued from any of said terminals isreceived by said base apparatus and information is transmitted from saidbase apparatus to one or more of the plurality of terminals by radiocommunication between the terminals and said base apparatus, said methodcomprising the steps of: receiving commands issued from any of saidterminals, said commands comprising both competitive commands andnon-competitive commands; determining whether the received command is acompetitive command whose acceptance can result in a disturbance ofinformation reception of any other of said terminals; rejectingacceptance of the command if it is determined that said received commandis a competitive command; and issuing a notification of the rejection ofthe command to the terminal that has issued the command; whereby thedisturbance caused by an acceptance of a competitive command to otherterminals that are under a receiving state is minimized.
 2. The commandprocessing method of claim 1, further comprising the steps of: setting apriority order among said plurality of terminals; if it is determinedthat said received command is a competitive command, determining whethersaid priority order of said terminal issuing said command is higher thanthat of any other of said terminals currently receiving data; if it isdetermined that said priority order of said terminal issuing saidcommand is higher than that of any other of said terminals currentlyreceiving data, accepting said command; and issuing a notification ofsaid acceptance of said command to said other terminals currentlyreceiving data.
 3. The command processing method of claim 1, furthercomprising the steps of: setting a predetermined time interval; if it isdetermined that said received command is a competitive command,determining whether said pre-determined time interval has elapsed sincethe issuance of a command implementing a procedure currently inoperation; if it is determined that said predetermined time interval haselapsed, accepting said command; and issuing a notification of saidacceptance of said command to said other terminals currently receivingdata.
 4. The command processing method of claim 1, further comprisingthe steps of: inquiring of said other terminals receiving data whether aparticular command may be accepted; and if a response to said inquiryfrom all of said other terminals consents to acceptance of saidparticular command, accepting said particular command.
 5. A radiocommunication apparatus for a radio LAN (Local Area Network) system thatincludes a plurality of terminals and at least one base apparatuswherein a command issued from any of said terminals is received by saidbase apparatus and information is transmitted from said base apparatusto the terminals by radio communication between the terminals and saidbase apparatus, said base apparatus comprising: reception means forreceiving commands issued from any of said terminals, said commandscomprising both competitive commands and non-competitive commands;discrimination means for determining whether the received command is acompetitive command whose acceptance can result in a disturbance ofreception of data of any other of said terminals, and furtherdetermining, based on a result of the determination whether the receivedcommand is the competitive command, and whether or not the commandshould be accepted; and first transmission means for issuing, when saiddiscrimination means determines that acceptance of the command should berejected, a notification of the rejection of acceptance of the commandto the terminal which has issued the command; whereby the disturbancecaused by an acceptance of a competitive command to other terminals thatare under a receiving state is minimized.
 6. The radio communicationapparatus according to claim 5, further comprising: means for setting apriority order among said plurality of terminals; means for determiningwhether said priority order of said terminal issuing said command ishigher than that of any other of said terminals currently receiving dataif it is determined that said received command is a competitive command;means for accepting said command if it is determined that said priorityorder of said terminal issuing said command is higher than that of anyother of said terminals currently receiving data; and secondtransmission means for issuing a notification of said acceptance of saidcommand to said other terminals currently receiving data.
 7. The radiocommunication apparatus according to claim 5, further comprising: meansfor setting a predetermined time interval; means for determining whethersaid predetermined time interval has elapsed since the issuance of acommand implementing a procedure currently in process if it isdetermined that said received command is a competitive command; meansfor accepting said command if it is determined that said predeterminedtime interval has elapsed; and second transmission means for issuing anotification of said acceptance of said command to said other terminalscurrently receiving data.
 8. The radio communication apparatus accordingto claim 5, further comprising: means inquiring of said other terminalsreceiving data whether a particular command may be accepted; and meansfor accepting said particular command if a response to said inquiry fromall of said other terminals consents to acceptance of said particularcommand.
 9. A command processing method for a base apparatus connectingto a plurality of terminals wherein a command issued from any of saidterminals is received by said base apparatus and information istransmitted from said base apparatus to one or more of the plurality ofterminals, said method comprising the steps of: receiving commandsissued from any of said terminals, said commands comprising bothcompetitive commands and non-competitive commands; determining whetherthe received command is a competitive command whose acceptance canresult in a disturbance of information reception of any other of saidterminals; rejecting acceptance of the command if it is determined thatsaid received command is a competitive command; and issuing anotification of the rejection of the command to the terminal that hasissued the command; whereby the disturbance caused by an acceptance of acompetitive command to other terminals that are under a receiving stateis minimized.
 10. The method of claim 9, wherein the commands issuedfrom any of said terminals are received by radio communication betweenthe terminals and said base apparatus.
 11. A base apparatus connectingto a plurality of terminals wherein a command issued from any of saidterminals is received by said base apparatus and information istransmitted from said base apparatus to the terminals, said baseapparatus comprising: reception means for receiving commands issued fromany of said terminals, said commands comprising both competitivecommands and non-competitive commands; determining means for determiningwhether the received command is a competitive command whose acceptancecan result in a disturbance of reception of data of any other of saidterminals; rejecting means for acceptance of the command if it isdetermined that said received command is a competitive command; andtransmission means for issuing, when said discrimination meansdetermines that acceptance of the command should be rejected, anotification of the rejection of acceptance of the command to theterminal which has issued the command; whereby the disturbance caused byan acceptance of a competitive command to other terminals that are undera receiving state is minimized.
 12. The base apparatus of claim 11,wherein said command issued from any of said terminals and saidinformation from said base apparatus are received and transmitted,respectively, by radio communication.
 13. A base apparatus forcommunicating with at least a first terminal and a second terminal, eachterminal operable to send a command to said base apparatus, comprising:a reception section for receiving a first command from said firstterminal; a channel selector for selecting desired a informationtransmission channel in accordance with said first command received fromthe first terminal and for outputting video data and audio datatransmitted via said selected information transmission channel; acompression section for compressing said video data and audio dataoutputted from said channel selector; a transmission section fortransmitting said compressed video data and audio data to said firstterminal; and a control section for rejecting a second command from saidsecond terminal when said reception section receives said second commandwhile said transmission section is transmitting said compressed videodata and audio data to said first terminal, whether said second commandis a competitive command or is not a competitive command.
 14. The baseapparatus of claim 13, wherein said channel selector is a tuner.
 15. Thebase apparatus of claim 13, wherein said reception section and saidtransmission section are coupled to an antenna.